The long-range goal of this project is a genetic and biochemical study of membrane transport in Neurospora. Work is currently proceeding along four specific lines: (1) studies of the mechanism of energy coupling to the transport of K ion, phosphate, and glucose: (2) isolation and characterization of mutants defective in these transport processes; (3) purification of a plasma-membrane ATPase that may be involved in the electrogenic pumping of H ion ions out of the cell, thereby providing energy for the functioning of a variety of H ion -dependent cotransport systems; and (4) characterization of PO4 transport by isolating mitochondria, to see whether it is under the control of the nuclear or mitochondrial genome.